A typical automatic transmission receives input from a driver via a mode select lever that is movable between various shift positions, such as drive, reverse, park, or neutral. Typically this mode select lever is connected to a cable or linkage assembly that extends to a transmission shift lever. When the driver selects a specific shift position by actuating the mode select lever, the cable or linkage assembly actuates the transmission shift lever which causes the transmission to shift into the desired gear.
Various systems have been proposed to replace the mechanical cable and linkage assembly connections with electrical shifting systems. These electrical shifting systems produce electric signals, derived from driver input as to desired mode selection, which are transmitted to a power source that shifts the transmission shift lever. Two such systems are shown in U.S. Pat. No. 4,790,203 granted Dec. 3, 1988 to Tury et al. and U.S. Pat. No. 5,068,583 granted Nov. 26, 1991 to Gresham et al. Systems such as these are often expensive, take up a great amount of valuable packaging space, and require significant modification to the vehicle transmission. Thus, it is desirable to provide an electric shift apparatus that improves packaging, reduces systems cost, and which is easily installed onto existing transmissions with minimal modifications.